findAndReplacePattern.java

import java.util.*;

public class findAndReplacePattern{
	public static void main(String args[]){
		String words[] = {"abc","deq","mee","aqq","dkd","ccc"};
		String pattern = "abb";
		System.out.println(FindAndReplacePattern(words,pattern));
	}

	public static List<String> FindAndReplacePattern(String[] words, String pattern) {
        List<String> ans = new ArrayList<>();
        for (String word: words)
            if (match(word, pattern))
                ans.add(word);
        return ans;
    }

    public static boolean match(String word, String pattern) {
        Map<Character, Character> m1 = new HashMap<>();
        Map<Character, Character> m2 = new HashMap<>();

        for (int i = 0; i < word.length(); ++i) {
            char w = word.charAt(i);
            char p = pattern.charAt(i);
            if (!m1.containsKey(w)) m1.put(w, p);
            if (!m2.containsKey(p)) m2.put(p, w);
            if (m1.get(w) != p || m2.get(p) != w)
                return false;
        }

        return true;
    }
}